Subgroup analysis demonstrates improvement in patients who experienced at least one attack per week while on placebo

A phase 3 trial has demonstrated that, at the approved dose of 60 IU/kg, Haegarda (C1 esterase inhibitor subcutaneous [human]) reduced the median number of hereditary angioedema (HAE) attacks per month by 98% in patients who had frequent attacks, from a 16-week placebo period to a 16-week treatment period. In addition, the breakthrough attack rate—extrapolated to one year—was reduced from approximately 70 attacks per year for patients on placebo to approximately six attacks per year for the same patients when on Haegarda.

“Approximately 30% of HAE patients experience weekly attacks, and the majority of those attacks can be debilitating to daily living,” said Timothy Craig, DO, Professor of Medicine and Pediatrics at Pennsylvania State University Medical School in Hershey, Pennsylvania. “These data demonstrate the ability of Haegarda to effectively prevent HAE attacks in patients who have severe and frequent HAE attacks.”

The subgroup analysis was based on data from the phase 3 COMPACT trial. The subgroup analysis evaluated 21 severely impacted patients of the 43 study participants who received 60 IU/kg of subcutaneous C1-esterase inhibitor (C1-INH) and a corresponding placebo over a 16-week treatment period each. High attack frequency was defined as experiencing at least one HAE attack per week (on average, greater than or equal to four attacks per month) while on placebo.

Haegarda is a self-administered, plasma-derived concentrate of C1-INH injected twice weekly subcutaneously. It targets the root cause of HAE by replacing deficient or dysfunctional C1-INH protein, restoring C1-INH levels above 40%, which is proposed to reduce the risk of HAE attacks. Subcutaneous administration of C1-INH builds and maintains steady-state functional C1-INH levels within three to four doses of Haegarda.

The FDA approved Haegarda on June 22, 2017, for routine prophylaxis to prevent HAE attacks in adolescent and adult patients.

HAE is a rare and potentially life-threatening genetic condition that occurs in about one in 10,000 to one in 50,000 people. HAE is caused by deficient or dysfunctional C1-INH, a protein in the blood that helps to control inflammation. Inadequate amounts of properly functioning C1-INH can lead to the accumulation of fluid in body tissues, causing considerable swelling referred to as angioedema. HAE attacks can affect many parts of the body and can spread to multiple sites, including the face, abdomen, larynx, and extremities. Patients who have abdominal attacks of HAE can experience extreme pain, diarrhea, nausea, and vomiting caused by swelling of the intestinal wall. HAE attacks that involve the face or throat can result in airway closure, asphyxiation, and, if left untreated, death.

The new findings were presented in an oral abstract session at the 2017 American College of Allergy, Asthma & Immunology annual scientific meeting.